1. Field of Invention
The present invention relates to a cutting apparatus, and more particularly to a cutting apparatus comprising a blade rotation arrangement for facilitating rotation of a cutting blade in a secure and convenient manner.
2. Description of Related Arts
A conventional cutting apparatus, such as a rotating knife, an elongated handle having supporting cavity formed therein, and an elongated blade rotatably supported in the supporting cavity for rotatably extending out of the elongated handle to cut a desirable object. The elongated blade usually has two opposed end portions crafted and designed to accomplish two different cutting purposes. For example, one end portion of the elongated blade may have a regular cutting blade while the other end portion has a plurality of teeth formed thereon so as to allow a user to use it as a mini saw.
This kind of conventional rotating knife usually has an actuation device provided on the elongated handle for normally locking a position of the elongated blade. When the actuation device is actuated, the elongated blade is unlocked and a user is able to rotate the elongated blade. The purpose of this conventional rotating knife is that the user may selectively utilize two different kinds of blade through rotating the elongated blade mounted on the elongated handle. There exist a number of disadvantages in associated with this conventional rotating knife, these disadvantages will be discussed below with reference to U.S. Pat. No. 7,124,510 to Frazer.
Referring to FIG. 3 and FIG. 3A of '510 patent, the rotating knife comprises a handle having two side pieces joined together by threaded fasteners. Each side piece has a thin, flat liner, preferably metal, secured to the remainder of the handle side pieces. One of the side pieces has a recess for the locking mechanism to operate. The locking mechanism includes a lever and a lock pin pivotally carried by the front end portion of the lever (by another small axle) and protrudes through aligned holes in the liners and the blade. In other words, the locking of the blade is accomplished solely by means of the lock pin penetrating through the liners and the blade. This structure is very weak in strength, especially when the lock pin is pivotally moved to lock and unlock the blade and is itself carried by a small axle. When the rotating knife has been used for a prolonged period of time, the lock pin or the small axle may break easily and the locking mechanism will fail to operate.
Furthermore, the lever is pivotally mounted to the handle through another pivot pin. When the user wishes to unlock the blade, he or she needs to press on the lower end of the lever so as to pivotally disengage the lock pin from the blade and the liners. Again, it is rather easy for this pivotal mechanism of the lever to fail, especially when the rotating knife is used in extreme conditions, such as in outdoor environment during hiking, camping, or even in outdoor work.
In addition, one may appreciate from FIG. 3A of '510 patent that when the lever is pivotally to unlock the blade, the blade is kept unlocked until the lock pin is pivotally moved to engage with the blade again. The lever is normally biased by the spring mounted at a lower end portion thereof so as to normally exert an outward pulling force to the lower end portion of the lever. As a result, when the elasticity of that spring looseness, the lever may accidentally disengage from the blade and the blade is accidentally unlocked. This imparts potential safety issues for the knife disclosed in '510 patent.
Since the blade is kept unlocked until the lock pin is pivotally moved to engage with the blade again, the user has to manually determine if the blade is rotated to a proper orientation. If the blade is not properly orientated but the user erroneously determines that the blade is in the proper orientation, such as aligning with the handle, the cutting performance of the knife will be affected.